Many of the electronic systems that are present on an airplane are temperature sensitive and prone to premature failure if subjected to extreme heat. For this reason, airplanes must have cooling systems that maintain a reasonable temperature within the airplane while the aircraft is not in use in order to maintain the integrity of the electronic systems aboard the airplane. Most modern airport terminals have cooling systems that can be attached to an airplane to regulate its temperature while it is parked at the airport terminal. However, self-contained, on-board cooling systems are carried on airplanes to cool the electronic systems when an external cooling system is not available, for example, when the airplane is not parked at a terminal or is parked at a terminal where an external cooling system is not present. On-board cooling systems typically utilize large, petroleum-based motors for operating the cooling system and any other systems on the airplane that require power. However, such systems are not efficient, as the motors must run for one to two hours in order to sufficiently cool the electronic systems on board the airplane. Consequently, the operation of petroleum-based motors in conjunction with airplane cooling can be very expensive and is therefore undesirable in the aviation industry.
As an alternative to petroleum-based motors, electrical motors have been used to power cooling systems on airplanes. Of course, electrical motors must be provided with an electrical power supply so they may operate. Thus, when an airplane is retrofitted so that an electrical cooling system may be installed, the electrical cooling system must ordinarily be interconnected with the electrical systems on the airplane, so that the cooling system may be powered by a ground power unit. Such ground power units are ordinarily located at airports for use by aircraft that are parked there. The ground power units are connected to the aircraft using an electrical cable that is connected to an electrical connector that extends through the fuselage of the airplane. However, interconnecting the electrical cooling system with the electrical systems of the airplane would require reevaluation of the air worthiness of the airplane. Thus, the expense of such a design change would outweigh the benefits obtained by using the electrically-operated cooling system, and thus, the design change would not be warranted.
Before now, a power adapter for an aircraft that connects a ground power unit both to the electrical system of the aircraft through a power connector in the fuselage, as well as directly connecting the ground power unit to an on-board electrical device, such as an electrical air-conditioning unit, has not been known.